Bots are social media accounts that automate interaction with other users, and political bots have been particularly active on public policy issues, political crises, and elections. We collected data on bot activity using the major hashtags related to the U.S. Presidential Election. We find that that political bot activity reached an all-time high for the 2016 campaign. (1) Not only did the pace of highly automated pro-Trump activity increase over time, but the gap between highly automated pro-Trump and pro-Clinton activity widened from 4:1 during the first debate to 5:1 by election day. (2) The use of automated accounts was deliberate and strategic throughout the election, most clearly with pro-Trump campaigners and programmers who carefully adjusted the timing of content production during the debates, strategically colonized pro-Clinton hashtags, and then disabled activities after Election Day.